Field of the Invention
The present invention relates to a process cartridge and an image forming method in which the process cartridge is detachable.
Description of the Related Art
In a recent technological trend in an electrophotographic image forming apparatus, the apparatus has been required to have various characteristics such as an additionally high speed, high reliability over a long time period, a long lifetime, and a reduced space and a reduced power consumption in addition to high definition, high quality, and high image quality. In such electrophotographic method, a process cartridge being detachably mountable to the main body of the image forming apparatus has been frequently used.
While the process cartridge is increased in volume, a restriction on the size of the process cartridge is required from the viewpoints of a reduction in size of the apparatus and its space savings. Accordingly, in recent years, a direction toward achieving compatibility between the high reliability over a long time period, and the size reduction and the space savings by packing a toner, which is intended to be reduced in consumption through the control of its shape and chargeability, into the process cartridge at a high density has been required.
In view of the foregoing, an attempt has been made to achieve the high-density packed process cartridge.
Japanese Patent Application Laid-Open No. 2004-118093 provides an example in which a toner obtained by a polymerization method is loaded at a high density. However, the flowability of the toner is so high that air is included at the time of the loading and hence it takes a long time period to load the toner at a high density. In addition, when an image having a high print percentage is continuously output, a problem such as a reduction in image density occurs.
Japanese Patent Application Laid-Open No. 2006-350309 provides an example in which a toner obtained by a pulverization method is loaded at a high density. However, when the toner is loaded at an additionally high density, the toner is not stirred well and hence an image failure occurs. In particular, it has been difficult to achieve compatibility between the high-density packing of the toner into a process cartridge intended to have a larger volume and a longer lifetime, and stable developability in the toner that has been loaded at a high density.